A threshold model for gay marriage
| Gabriel |
In a post at Volokh Conspiracy, Dale Carpenter notes that many states have recently made a push towards gay marriage and this may reflect a “bandwagon” effect. Although most of my work is on pop culture, I’ve experimented with applying these models to state policy and it looks like there’s rather a lot of the kind of bandwagon thing that Carpenter is describing. In my secondary analysis of the Walker data, I found that the typical law spreads from state to state via a mixed-influence curve very similar to that which Bass found for consumer appliances.
I think Carpenter’s analysis is basically accurate as far as it goes, but some of the details are a bit fuzzier than they ought to be. First, “bandwagon” is a vague term by which can mean any cumulative advantage process, be it cohesive contagion, structural equivalence contagion, information cascades, or network externalities. In quoting a post by Ryan Sager, Carpenter implies that it’s mostly cascades. Second, Carpenter talks a lot about public opinion, but this isn’t really the issue, rather what really matters are the opinions of policy makers. For a long time it has been apparent that courts are much more open to gay marriage than democratic policy institutions, but increasingly we are now seeing a gap open between small-d democratic plebiscites and small-r republican state legislatures. For instance in California, the gay marriage issue lines up as the courts and the state legislature (pro) versus plebiscites and the governor (con). It seems that part of the reasons for the public opinion versus policy maker opinion gap is that educated people are more cosmopolitan and part has to do with the coalition politics of the Democratic party (for instance, in California many Democratic legislators voted for AB 849 whose districts voted for prop 8, likewise I would be very surprised if gay marriage is as popular with DC residents as with the DC city council).
When you combine these two vagaries of what is the exact cumulative advantage mechanism and cumulative advantage among whom, you come to a very interesting synthesis about how this may be working. I would suggest that a very large part of the issue is not an information cascade but a network externality among policy makers. These points are subtly different. In an information cascade we don’t know the value of things and so we figure that the consensus about it is informative. With network externalities the consensus itself implies value so the important thing is to be with the consensus.
A simple recent example of network externality dynamics is the format war between HD-DVD and Blu-Ray. Aside from Sony no movie studio really cared about the differences between the formats (and to the extent they did care, they preferred HD-DVD which was cheaper to manufacture) but they cared a lot about making sure they didn’t commit to the wrong format because nobody wants to own a bunch of equipment and a big disc inventory for a format that consumers have rejected. The studios dithered about making a big commitment to either format until Sony basically sent its Playstation brand on a suicide mission to build a critical mass of Blu-Ray players at which point the remaining studios abandoned HD-DVD almost immediately.
Likewise at a certain point gay marriage began to seem inevitable (a prediction shared even by many people who see this as unfortunate). Now many ordinary people would say popular or not is irrelevant, I’d support [marriage equality / traditional marriage] even if everyone disagreed with me. However there is another way to think about it as “being on the right side of history,” a concern made more salient by the frequent analogies drawn to Jim Crow and especially to miscegenation laws. The Sager piece alludes to some pro-segregation pieces published by National Review in the 1950s and this is interesting. At the time these were not considered crackpot ideas (they were probably more mainstream than NR‘s pro drug legalization pieces in the 1990s) but in retrospect they are repulsive. I think this is a big part of what’s going on here, policy makers are not just judging themselves via public opinion today but against what they project public opinion to be in the future. Since they (probably accurately) perceive that gay marriage will become more popular over time they are calibrating their actions to this future metric rather than current opinion, which is basically divided (at present the median voters opposes gay marriage per se but favors the Solomonic “civil unions” compromise). In contrast, some voters care about “being on the right side of history” but many do not, in part because unlike legislators their votes are not recorded and thus if they change their minds in the future (or if they remain the same but their opinions become less popular than they are currently) they will suffer little problem from the inter-temporal contradiction.
(Note: I’m interested in this as a question of diffusion, not a substantive one of morality or policy, and will enforce this in the comments.)